Note 3 - Investments in Debt Securities - Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
One year or less, amortized cost	$ 120	$ 2,687
One year or less, fair value	122	2,692
Amortized cost	120	2,687
Fair value	$ 122	$ 2,692

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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+ Details